The present invention relates to variable-beam headlights for vehicles.
It concerns more particularly headlights which are capable of generating, by means of a single light source, beams of the main-beam type with different light distributions.
Headlights of this type have already been proposed, notably in the French patent application published under the No 2 727 497. The main advantage of such headlights is that the light distribution which they generate is adapted to the vehicle driving conditions. In general, the light distribution varies with the speed of the vehicle, in order to illuminate the areas close to the vehicle at low speed (broad beam) and to favour illumination of the road as far away as possible at high speed (narrow beam).
One object of the present invention is to provide a headlight of the aforementioned type with good optical performance and robust operation.
For this purpose, the invention proposes a headlight, notably for a vehicle, having a first, generally concave, reflector, a lamp mounted fixedly in the first reflector and carrying a light source, and a second reflector received in the concavity of the first reflector, in which the second reflector is able to move between an extreme position in which the headlight generates a broad beam and an extreme position in which the headlight generates a narrow beam.
The invention also proposes the following characteristics:
the first reflector has at least one bearing area which receives the light from the light source when the second reflector is in one of the extreme positions, and which is masked by the second reflector when the latter is in the other extreme position;
the second reflector generates a broad beam in one of the extreme positions and a narrow beam in the other extreme position;
the first reflector has a base area which receives light from the light source whatever the position of the second reflector, and which reflects the light in a broad beam;
the second reflector is able to move between an advanced extreme position, in which it generates a narrow beam, and a retracted extreme position, in which it generates a broad beam and masks at least one bearing area of the second reflector;
the second reflector is mounted on a rod-shaped support which passes through an opening in the first reflector and which is connected to a drive device;
the second reflector is produced in two parts joined by the support;
the illumination along the optical axis in narrow beam is greater than the illumination along the optical axis in broad beam and the illumination at 101xc2x0 azimuth in narrow beam is less than the illumination at 10xc2x0 azimuth in broad beam;
the illumination along the optical axis in narrow beam is greater than the illumination along the optical axis in broad beam and the illumination at 15xc2x0 azimuth in narrow beam is less than the illumination at 15xc2x0 azimuth in broad beam.